NATURAL SCIENCES OF PHILADELPHIA. 141 



vide measurements ; by the very different color of the npi^er parts ; and by 

 the fuliiiinous black instead of white nnder tail coverts. 



The Puf^iiHs ijelcuanus is ligliter colored above than is ancjJorvm, and there- 

 for*; this species approaches it in this respect. But ijdcuanus is muoli larger 

 than the present species, and has white under tail coverts like anglorum ; so 

 that it is impossible to confounrl it with opinthomeJas. 



Still mure different is this species from the P. iiufjax, Solander, from the 

 Australian seas. This latter is a very diminutive species, much smaller even 

 than ohsctints, the wing being only about 6-} inches from the carpus. It also 

 has the white of the throat extending far up on the sides of the head and 

 neck, and white under tail coverts ; characters diametrically opposed to those 

 which obtain in the present species. 



I am acquainted with no other species to whicb the present bears any sort 

 of resemblance. I trust that I have so fully and correctly indicated its cha- 

 racters and relationships, that its introduction, even into this peruliarly in- 

 tricate ^^roup, will be the cause of no confusion or uncertainty regarding it. 



Two fine examples are contained in the Smithsonian Museum, both col- 

 lected by Mr. John Xantus at Cape St. Lucas, Lower California. (Smiths. 

 Catalogue, Nos. 1G,990, 16,991.) 

 PuFFiNus NUGAx (Solander. ) 



Procellaria nur;ax, Solander, Schlegel, Mon. Proc. Mus. Pays-Bas, 18G3, 



p. 31. Pujffinus nugax, Bonaparte, Consp. Av., ii. 1856, p. 205. 

 Pvffinus assimilis, Gould, P. Z. S., 1837, v. p. 156. Id. Ann. et Mag. N. 



H. xvi. Id. Birds Aust., vii. pi. 56. 

 "Procellaria aii.stralis, Eyton," (Bp.) 



Habitat. — Australian seas. 



A fine suite of this well marked species is in the collection of the Philadel- 

 phia Academy. Its relationships are closest with P. obsctirtis, but the dif- 

 ferences are sufficiently obvious on comparison. It is the very smallest 

 known species of Pvffinus, being appreciably less than the obicurns. It is 

 hardly lO'SO inches in length ; the wings from the carpus only about 6^ ; th 

 tail avei'ages 2-75 ; the bill about one inch; the tarsus 1^^ ; the middle toe 

 about the same. The color of the upper parts is about the same as in P. ob- 

 scurus, or a very little lighter ; the feathers generally with appreciably darker 

 tips. A striking diagnostic feature is found in the extent to which the white 

 of the under parts mounts up on the sides of the head and neck, which is 

 greater than in any other species. The inferior caudal tectrices are usually 

 entirely pure white. The under surfftces of the wings are [lure white, and 

 the inferior aspect of the inner webs of the primaries are dull whitish, being 

 much ligliter than are these parts in obscurus. The bill is dusky horn color. 

 The tarsi are greeenish yellow ; the webs bright chrome yellow. 



The preceding paragraph shows the points in which the species differs 

 from obscurus. It is too distinct from anr/lorum or i/elcuanus to require com- 

 parison. It cannot be confounded with my P. opisthomelas, since- the latter 

 is nearly as much larger than obscurus as nur/ax is smaller ; has the colora- 

 tion of the sides of the head and neck very different, (compare descriptions ;) 

 has black instead of white under tail coverts, etc. 



I have not an opportunity of examining the original description of nugax 

 by Solander, but all authors agree that it is the species subsequently named 

 assimilis by Gould. I do not know where the species is called australis by 

 Eyton, but quote the name on the authority of Bonaparte. 



Anahjtical Synopsis of the Genera and Species of PuffinEjE. 



Family PROCELLARIDyE. 



Subfamily PROCELLARINiE, 



Section PuFFiNEi=E. 



Char. — Tail of twelve much graduated feathers. Bill long, compressed, 



1864.] 



